Our land is totally flat except for (of course) the area around the barn. The people before us just stick built it on top of the ground, which of course means that it is sinking into a mud pit. We are intending to get out there this spring and do some major earthworks to direct the water somewhere else in a brave attempt to keep the barn from floating down the creek. The pastures are also pretty wet and need something to collect the excess.

My question is ... does it matter how one does the swales on flat land? Can I just put them in the most logical places, or is there some way of determining contour on flat land?

On flat land one thing I have seen my neighbors do is create ponds and use the excess dirt removed to build long terraced mounds.
If you have the rock or other means to build retaining walls than terraces are useful. If not and you have alot of wood you can take the dirt and cover the wood to make mounds that you can plant into. Just have to remember to pull all the top soil off and save it to apply to mounds last. You will find the ponds provide a place for water to go to in heavy rains. The mounds can be used to direct water.

My land is mostly flat and we have water problems on our driveway. I kind of eyeballed my swales with thoughts going into directing water off the driveway. So my swales are off contour and water does flow from the driveway, into and down the swales.

So if I were you I'd do the most logical swale set up for your land. Further out on my property I'll be looking to do things on contour but around the driveway it's all off and all for drainage.

Thanks. Yeah, around the barn the water needs to go off, period. There's already a drainage ditch on one side, but unfortunately there's a nice dip between it and the barn, so not much water goes there. I'll just run the swales towards it, assuming I can get it to dry out enough that the swales will hold. It's seriously like wet concrete out there ... just oozes back into wherever you try to move it from. If we have a wet spring, it's gonna be July before we get this done, but we WILL get it done.

elle sagenev wrote:My land is mostly flat and we have water problems on our driveway. I kind of eyeballed my swales with thoughts going into directing water off the driveway. So my swales are off contour and water does flow from the driveway, into and down the swales.

So if I were you I'd do the most logical swale set up for your land. Further out on my property I'll be looking to do things on contour but around the driveway it's all off and all for drainage.

I would think best bet would be to run the swales, or ditches along your driveway to swales that are on contour which will allow you to soak in all that water

A swale is a ditch on contour
A keyline is a ditch almost on contour (could be to a pond in the center or off to the edges)
A drainage ditch like the ones they use to drain swamps are just the same ditches that are off contour.

Sometimes I even call berms elevated ditches too. But mostly if you have too much water you can get it off the land as soon a possible, or send it all as quickly as possible to a "sacrificial pond area" or you can send from the middle of the land/contour to the end of the land/contour.  But overall if your land is already a swamp/lake there is no need to build underwater swales.

An important part of using swales is that they cause water to either move around the proerty, or hold water in shallow sections so that it soaks into the ground.
Water retention in dry land areas is essential for good soil health and thats what swales are best for.
Keyline channels as detailed by Yoemans, are best for moving water slowly.